Amasa

Amasa's father was Jether (1 Kings 2:5,32, 1 Chronicles 2:17) who was also called Ithra (2 Samuel 17:25).

[2] When Absalom rebelled against David and won over the tribes of Israel (2 Samuel 15), Absalom appointed Amasa as commander over the army (2 Samuel 17:25), in effect replacing Joab, who had served as commander for David.

After the revolt was crushed and Absalom died (2 Samuel 18:1–17), David was invited back to Jerusalem and restored as king.

[4] David's appointment of Amasa has been interpreted as "a bold stroke of policy, to promise the post of commander-in chief to the general of the rebel army".

[5] While being fiercely loyal to David, Joab was also suspicious of any potential rivals for Joab's power or threats to David's kingdom, and had no qualms about taking the lives of any who might stand in his way (e.g., Abner: 2 Sam 3:27, and Absalom: 2 Sam 18:14).